The first record of Lower Cretaceous otoliths from the Kimigahama Formation (Barremian) of the Choshi Group, Chiba Prefecture, Japan

The Lower Cretaceous otolith assemblage from the Kimigahama Formation (Barremian) of the Choshi Group, Chiba Prefecture, Japan, is described. The Kimigahama Formation consists of bioturbated silty sandstone, sandy siltstone, and hummocky and swaley cross-stratified sandstone, representing an offshore to shoreface depositional environment. A total of five otolith types were identified, including undetermined Teleostei, Pterothrissinae, Elopiformes, Argentinidae, and Ichthyotringidae. Among them, Ichthyotringidae from Kimigahama Formation is the oldest Ichthyotringoidei. Based on the shallow marine setting of the Kimigahama Formation, the Barremian Pterothrissinae and Argentinidae in East Asia inhabited shallow marine environments, whereas the habitat of extant species is the deep sea. Furthermore, our new data on Pterothrissinae, Argentinidae, Ichthyotringoidei, and Elopiformes from Barremian strata in the northwestern Pacific indicate that these taxa exhibited a cosmopolitan distribution in the Pacific, Tethys, and Atlantic seas during the middle Early Cretaceous.